If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
x+12/x = 7 // - 7
x+12/x-7 = 0
1*x^1+12*x^-1-7*x^0 = 0
(1*x^2-7*x^1+12*x^0)/(x^1) = 0 // * x^2
x^1*(1*x^2-7*x^1+12*x^0) = 0
x^1
x^2-7*x+12 = 0
x^2-7*x+12 = 0
DELTA = (-7)^2-(1*4*12)
DELTA = 1
DELTA > 0
x = (1^(1/2)+7)/(1*2) or x = (7-1^(1/2))/(1*2)
x = 4 or x = 3
x in { 3, 4}
x in { 3, 4 }
| b=28a | | 1/7x63 | | x^2-3x-40=x | | 4x+3/5=2x-1/2 | | 3x+5y+2z=-7 | | 14=4+5n+5 | | x(5x+6)=2x^2-7x+30 | | -5x+6y=4 | | -4(4X+Y)+4(2X-2Y)= | | 8y=78-14 | | -x-2y+z=10 | | n-6+n=-22 | | x(5x+2)=2x^2-12x+5 | | x+3z=12 | | n-6tn=-22 | | 3x-1/4=2x-3 | | 4(2x+9)=48 | | 5y+7*2+4y+9*7=14 | | 2x+6=-114-20x | | (x/5)+20=(-x/15)-5 | | 5z-4z+9=6 | | 9(b-5)= | | 6-6x+5=17 | | 3(x-a)+4b=4x+a | | 8/x=24 | | 2=w/9-2 | | 9*(x+5)-4=52 | | r/11=5 | | 3d=d^2 | | -8x+4=16x-9 | | 5(x+4)=9x+32 | | 5(5x+5)=55 |